As the consequence of the development of electronic technology, no matter on school lectures or during department seminars, electronic whiteboards are used more and more widely. This kind of product is able to convert symbols written on the whiteboard to electronic signals in time, and transmits the electronic signals to the connected computer, then completes teledata communication, such as editing data, printing data, transmitting data, etc., directly by the computer. Because the induction area is relatively large, now the existing electronic whiteboard neither can be made, for example, the electromagnetic induction type made by means of printed circuit board erosion; nor can use the resistance induction configuration as the touch screen, thereby the electronic whiteboard cannot determine the location where the instruction occurs and move cursor by using resistance induction generating device or inductance induction generating device, etc., as hand-writing panel, but by using the method of supersonic transmission and reception between input pen and whiteboard to control, while it is still high cost, which limits the application of this kind of product widely. Therefore, the existing products have problems such as obviously low recognition rate, low precision, high cost, and difficulty in manufacture, etc.